Improvements in and relating to managing pdu sessions in a telecommunication system

ABSTRACT

The disclosure relates to a communication method and system for converging a 5 th -Generation (5G) communication system for supporting higher data rates beyond a 4 th -Generation (4G) system with a technology for Internet of Things (IoT). The disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as a smart home, a smart building, a smart city, a smart car, a connected car, health care, digital education, smart retail, security and safety services. Methods and apparatuses for supporting a plurality of PDU sessions are provided.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. §119(a) of a Great Britain patent application number 2015676.6, filed onOct. 2, 2020, in the Great Britain Intellectual Property Office, and ofa Great Britain patent application number 2113942.3, filed on Sep. 29,2021, in the Great Britain Intellectual Property Office, the disclosureof each of which is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to proximity services (ProSe) within a 5^(th)Generation (5G) telecommunication network. More particularly, thedisclosure relates to providing methods and apparatuses for supporting aplurality of protocol data unit (PDU) sessions.

2. Description of Related Art

To meet an increasing demand for wireless data traffic since deploymentof 4^(th)-Generation (4G) communication systems, efforts have been madeto develop an improved 5^(th)-Generation (5G) or pre-5G communicationsystem. Therefore, the 5G or pre-5G communication system is also calleda ‘Beyond 4G Network’ or a ‘post long-term evolution (LTE) System’. The5G communication system is considered to be implemented in higherfrequency (millimeter (mm) Wave) bands, e.g., 60 GHz bands, so as toaccomplish higher data rates. To decrease propagation loss of the radiowaves and increase the transmission distance, the beamforming, massivemultiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO),array antenna, an analog beam forming, large scale antenna techniquesare discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud radio access networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,coordinated multi-points (CoMP), reception-end interference cancellationand the like. In the 5G system, hybrid frequency shift keying (FSK) andquadrature amplitude modulation (QAM) frequency quadrature amplitudemodulation (FQAM) and sliding window superposition coding (SWSC) as anadvanced coding modulation (ACM), and filter bank multi carrier (FBMC),non-orthogonal multiple access (NOMA), and sparse code multiple access(SCMA) as an advanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof Things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The internet ofeverything (IoE), which is a combination of the IoT technology and theBig Data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “Security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing Information Technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies, suchas a sensor network, machine type communication (MTC), andmachine-to-machine (M2M) communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud radioaccess network (RAN) as the above-described Big Data processingtechnology may also be considered to be as an example of convergencebetween the 5G technology and the IoT technology.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providemethods and apparatuses for supporting a plurality of protocol data unit(PDU) sessions.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure, a method of managing atelecommunication network, wherein a first user equipment (UE) is incommunication with a core network of the telecommunication network,wherein the first UE establishes a PDU session with the core network andwherein capability information related to an ability of the first UEand/or the telecommunication network to support a plurality of PDUsessions is transmitted in at least one direction between the first UEand the core network is provided.

In an embodiment the method of managing is a method of managing aproximity services, ProSe, connection.

In an embodiment of the disclosure, first capability information istransmitted from the first UE to the core network and second capabilityinformation is transmitted from the core network to the first UE.

In an embodiment of the disclosure, the first UE is in communicationwith a core network of the telecommunication network, wherein a secondUE establishes a PDU session with the core network and whereincapability information related to an ability of the second UE and/or thetelecommunication network to support a plurality of PDU sessions istransmitted in at least one direction between the second UE and the corenetwork.

In an embodiment of the disclosure, the second UE is a remote UE.

In an embodiment of the disclosure, the second UE performs the exchangeof capability information with the network after establishing a ProSecommunication (e.g., using PC5 link) with the first UE via which thesecond UE communicates with the network.

In an embodiment of the disclosure, the first UE is one of a relay UE, aLayer-2 UE to network relay UE and a Layer-3 UE-to-network relay UE.

In an embodiment of the disclosure, the plurality of PDU sessionsexceeds sixteen.

In an embodiment of the disclosure, the plurality of PDUs are of thetype “unstructured”.

In an embodiment of the disclosure, the first or second capabilityinformation comprises either information that additional PDUs aresupported or a specific number of PDUs that are supported.

In an embodiment of the disclosure, the first or second capabilityinformation comprises bits within a message having another function orthe first or second capability information is associated with its ownrespective Information Element.

In an embodiment of the disclosure, in the telecommunication network, anaccess and mobility management function (AMF) selection of a sessionmanagement function (SMF) is dependent upon the SMF's ability to useextended PDU Session ID values.

In an embodiment of the disclosure, the first UE establishes a ProSeconnection to a second UE, utilizing one of the plurality of PDUsessions, or the second UE establishes a ProSe connection to a first UE,utilizing one of the plurality of PDU sessions.

In accordance with another aspect of the disclosure, a UE, operable tocommunicate with a telecommunication network and to establish a PDUsession with a core network of the telecommunication network, whereinthe UE is further operable to transmit capability information related toan ability of the UE to support a plurality of PDU sessions or toreceive capability information related to an ability of thetelecommunication network to support a plurality of PDU sessions isprovided.

In accordance with another aspect of the disclosure, a telecommunicationnetwork operable to communicate with a UE and to establish a PDU sessionwith the UE, wherein the telecommunication network is further operableto transmit capability information related to an ability of thetelecommunication network to support a plurality of PDU sessions or toreceive capability information related to an ability of the UE tosupport a plurality of PDU sessions is provided.

In an embodiment of the disclosure, the telecommunication networkcomprises a core network and a radio access network (RAN) andcommunication with the UE is performed via the RAN.

In accordance with another aspect of the disclosure, a system comprisingthe telecommunication network of the third aspect and the UE of thesecond aspect is provided.

In an embodiment of the disclosure, the UE and the network exchangenewly defined capability information to indicate whether increasednumber of PDU session (ID) can be supported.

In an embodiment of the disclosure, the capability information may be inthe form of new bits or explicit numbers indicating the maximum numberof PDU session (ID) that can be supported by the UE and the network. Inan embodiment, the AMF's selection of an SMF takes into account theability of an SMF to handle or use extended PDU session ID values.

In an embodiment of the disclosure, the capability information about thesupport of more than 15 PDU session identity may also be performed onthe RRC layer i.e., using RRC messages. The RRC messages may be existing(i.e., known in the art) or new messages, defined to implement thedisclosure. The UE may autonomously indicate its capability to supportmore than 15 PDU session identity using any RRC message, and possiblyalso indicate the actual number of PDU session (identity) that can besupported using any of the mechanisms described earlier. Similarly, theRAN may use an RRC message to indicate whether or not. and possibly theactual number of PDU session (identity). that the RAN supports using anyof the mechanisms described earlier.

In an embodiment of the disclosure, the RAN provides the UE's capabilityto support more than 15 PDU session (identity) and possibly provides theactual number that the UE supports based on a capability that the RANhad received optionally from the UE optionally using any RRC message.

In an embodiment of the disclosure, when the AMF determines to reportthe capability of the network to support more than 15 PDU session(identity) to the UE (as described earlier), the AMF takes into accountthe ability for the RAN and optionally the SMF(s) to support more than15 PDU session (identity). For example, if the RAN does not support morethan 15 PDU session identity, then the AMF indicates that the networkdoes not support more than 15 PDU session identity. For example, whenprocessing the establishment of a PDU session with an identity that islarger than 15, the AMF may allow or reject the establishment based onthe support of the RAN and optionally also the SMF of a PDU sessionidentity that is larger than 15.

In an embodiment of the disclosure, the RAN may broadcast whether thenetwork supports more than 15 PDU session identity and may alsobroadcast the actual number that is supported.

In an embodiment of the disclosure, the RRC layer in the UE may indicateto the NAS layer whether the network supports more than 15 PDU sessionidentity and may also indicate the actual number that is supported inthe network. The RRC layer may get this information using eitherbroadcast method (e.g., based on broadcast information by the RAN) orusing dedicated RRC signaling where for example this signaling isreceived from the RAN.

In an embodiment of the disclosure, the NAS layer (e.g., the SGSM entityand/or the SGMM entity, where the latter may also provide thisinformation to the former as described next) may determine whether ornot the network supports more than 15 PDU session (identity) andoptionally the actual number that is supported based on information thatis received from the network using NAS signaling (as described earlier)or that is received from the RRC layer in the UE.

In an embodiment of the disclosure, when the UE moves into an area,e.g., a new RAN coverage or an area in which there is a different SMF,such that the number of PDU sessions that can be supported by thenetwork changes (e.g., increases to more than 15, or decreases to 15 orless), then the network (e.g., AMF, SMF, RAN) may inform the UE aboutthe actual number of PDU session identity that can be supported in thisarea.

In an embodiment of the disclosure, the number of PDU session ID that issupported in the network may be expected to be in all of the PLMN'sserving area, or may be valid/dependent only in the UE's currentregistration area, which may also include equivalent PLMNs. Based on anyof these, the UE may determine whether the supported number is per theentire PLMN or per a registration area. It may be the case that bydefault, a certain number of PDU session identity is assumed to besupported until the network indicates otherwise. This default number maybe at most 15 or more than 15 or any other number.

Note that the information as described above can apply to any UE and notjust a (layer 2 or layer 3) relay UE.

In an embodiment of the disclosure, the UE's PC5 discovery messages areadapted (from known related art messages) to indicate whether extendedPDU session (ID) are required/supported. Selection of such UEs willconsider this information.

In accordance with another aspect of the disclosure, a method performedby a UE is provided. The method of the UE includes transmitting, towardan AMF entity, a registration request message including firstinformation indicating whether the UE supports an increased number ofPDU sessions, receiving, from the AMF entity, a registration acceptmessage including second information indicating whether a networksupports the increased number of PDU sessions, and identifying whetherthe increased number of PDU sessions is allowed to be used based on atleast one of the first information or the second information.

In accordance with another aspect of the disclosure, a method performedby an AMF entity is provided. The method of the AMF entity includesreceiving, from a UE, a registration request message including firstinformation indicating whether the UE supports an increased number ofPDU sessions, and transmitting, to the UE, a registration accept messageincluding second information indicating whether a network supports theincreased number of PDU sessions, wherein whether the increased numberof PDU sessions is allowed to be used is based on at least one of thefirst information or the second information.

In accordance with another aspect of the disclosure, a UE is provided.The UE includes a transceiver, and at least one processor configured totransmit, toward an AMF entity via the transceiver, a registrationrequest message including first information indicating whether the UEsupports an increased number of PDU sessions, receive, from the AMFentity via the transceiver, a registration accept message includingsecond information indicating whether a network supports the increasednumber of PDU sessions, and identify whether the increased number of PDUsessions is allowed to be used based on at least one of the firstinformation or the second information.

In accordance with another aspect of the disclosure, an AMF entity isprovided. The AMF entity includes a transceiver, and a controllerconfigured to receive, from a UE via the transceiver, a registrationrequest message including first information indicating whether the UEsupports an increased number of PDU sessions, and transmit, to the UEvia the transceiver, a registration accept message including secondinformation indicating whether a network supports the increased numberof PDU sessions, wherein whether the increased number of PDU sessions isallowed to be used is based on at least one of the first information orthe second information.

Embodiments of the disclosure extend the number of PDU session ID thatcan be supported by a UE and enables the UE and network to exchangecapability information by this means. This, in turn, enables a relay UEto support a higher number of remote UEs, especially when the number ofremote UEs that require PDU sessions of Unstructured data is large (andabove 15).

Embodiments of the disclosure enable the network to support moresessions and, hence, more remote UEs. This is advantageous for anapplication service provider, which can then service more customers forits services. The required changes in the UE and the network are made toincrease the number of remote UEs that can be served, especially forUnstructured data sessions.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates a proximity services (ProSe) configuration accordingto an embodiment of the disclosure;

FIG. 2 illustrates protocol data unit (PDU) session identity codingaccording to an embodiment of the disclosure;

FIG. 3 illustrates PDU session identity 2 coding according to anembodiment of the disclosure;

FIG. 4 illustrates uplink data status coding according to an embodimentof the disclosure;

FIG. 5 illustrates allowed PDU Session Status coding according to anembodiment of the disclosure;

FIG. 6 illustrates PDU Session Status coding according to an embodimentof the disclosure;

FIG. 7 illustrates a structure of a user equipment (UE) according to anembodiment of the disclosure;

FIG. 8 illustrates a structure of a base station according to anembodiment of the disclosure; and

FIG. 9 illustrates a structure of a network entity according to anembodiment of the disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

In the following description of the disclosure, a detailed descriptionof relevant known functions or configurations incorporated herein willbe omitted when it may make the subject matter of the disclosureunnecessarily unclear. The terms which will be described below are termsdefined based on the functions in the disclosure, and may be differentaccording to users, intentions of the users, or customs. Therefore, thedefinitions of the terms should be made based on the contents throughoutthe specification.

In describing the disclosure below, a detailed description of relevantknown functions or configurations incorporated herein will be omittedwhen it may make the subject matter of the disclosure unnecessarilyunclear. Hereinafter, embodiments of the disclosure will be describedwith reference to the accompanying drawings.

In the following description, terms for identifying access nodes, termsreferring to network entities, terms referring to messages, termsreferring to interfaces between network entities, terms referring tovarious identification information, and the like are illustratively usedfor the sake of convenience. Therefore, the disclosure is not limited bythe terms as used below, and other terms referring to subjects havingequivalent technical meanings may be used.

Note that in the following description the embodiments of the disclosureare not limited to relay UEs only and hence the techniques set out canbe applied to any UE. Therefore, any reference to a relay UE should beconsidered to be an example of a UE in general and not only a relay UE.Note, also, that references to Unstructured PDU session types areexemplary only and embodiments of the disclosure can be applied to anyother PDU session type.

FIG. 1 illustrates a ProSe configuration according to an embodiment ofthe disclosure.

Referring to FIG. 1, a remote UE 10 is connected via a PC5 interface toa relay UE or UE to network relay 20. The relay UE 20 is connected via aUu interface to a next generation radio access network (NG-RAN) 30 whichconnects to the 5G core (5GC) 40. Ultimately, the 5GC 40 is incommunication with an application server (AS) 50 via an N6 interface.

Note that the general hardware configuration shown in FIG. 1 appliesequally to embodiments of the disclosure. Certain entities in theconfiguration are adapted as per embodiments of the disclosure.

The terms relay, UE-to-Network relay, relay UE, layer-2 relay UE orlayer-3 relay UE are used interchangeably throughout the disclosure.

Work undertaken in connection with 5G ProSe supports a User Equipment(UE)-to-network relay (hereafter referred to as relay UE) that enablesremote UEs to connect to the 5G core network and obtain services. Notethat the remote UEs are so termed because they are not in a coveragearea of the Radio Access Network (RAN) themselves and, hence, requireconnection via one or more relay UEs. The one or more relay UEseffectively extend the reach of the RAN.

The relay UE establishes a protocol data unit (PDU) session that is alsoused by the remote UE, where the procedures and details on how this isenabled depends on the PDU session type in question. For example, whenthe relay UE establishes a PDU session for IP traffic, several remoteUEs may use one of the relay UE's PDU sessions, since a remote UE'straffic may be mapped to, or identified with, a set of packet filters orservice data flows (SDFs). There can be 16 packet filters and hence 16SDFs for each quality of service (QoS) rule. Moreover, there can be 64different QoS flow identifiers (QFIs) per PDU session. This shows thatone QoS rule, of a PDU session, can be associated with several SDFs and,overall, there can be 64 QFIs for each PDU session. In theory, thismeans that there can be many more than 64 remote UEs that use one PDUsession from a relay UE. Note that this is possible by virtue of supportof more than one QoS rule for PDU sessions having the type IP orEthernet.

On the other hand, a PDU session of type “Unstructured” can only supportone QoS rule and that is the default QoS rule. Additionally, the set ofpacket filters of the default QoS rule must be empty. This means thatthere is no flexibility or means to multiplex traffic from more than oneremote UE on to the Unstructured PDU session of the relay UE. Hence,when a PDU session for type “Unstructured” is established by the relayUE, the PDU session can only be used by one remote UE.

The following is stated in the applicable standard definition (TR 23.752V0.5.0):

“IP type PDU Session and Ethernet type PDU Session can be used tosupport more than one Remote UEs while Unstructured type PDU Session canbe used to support only one Remote UE.”

Further, it should be noted that the relay UE that provides the servicesas described above is considered to be a Layer 3 (L3) relay UE. Section6.6 of the aforementioned standard definition provides furtherinformation on the procedures involved for the operations of an L3 relayUE, where the solution is considered to be one possible solution for arelay UE.

Every PDU session is uniquely identified by a PDU session identity (ID),where the PDU session ID can take a value between 1 and 15. This isillustrated in FIG. 2, which shows the PDU sessions possible, and thebit coding associated with each.

FIG. 2 illustrates PDU session identity coding according to anembodiment of the disclosure.

Referring to FIG. 2, Bits 1 to 8 of the second octet of every 5GSMmessage contain the PDU session identity Information Element (IE). ThePDU session identity and its use to identify a message flow are definedin the applicable standard.

FIG. 3 illustrates PDU session identity 2 coding according to anembodiment of the disclosure.

Referring to FIG. 3, the purpose of the “PDU session identity 2”information element is to indicate the identity of a PDU session in aSGMM message.

The “PDU session identity 2” information element is coded as shown inFIG. 3.

The “PDU session identity 2” is a type 3 information element with alength of 2 octets. The coding of the “PDU session identity 2” (octet 2)value is identical to the coding of the PDU session identity value asdefined in 3GPP TS 24.007.

The IEs shown in FIGS. 4 to 6 also contain a bitmap where each bitrepresents a PDU session ID.

FIG. 4 illustrates uplink data status coding according to an embodimentof the disclosure.

The purpose of the Uplink data status IE is to indicate to the networkwhich preserved PDU sessions have uplink data pending.

Referring to FIG. 4, the Uplink data status information element is atype 4 information element with minimum length of 4 octets a maximumlength of 34 octets.

PSI(x) shall be coded as follows.

PSI(0): Bit 1 of octet 3 is spare and shall be coded as zero.

PSI(1)-PSI(15):

0 indicates that no uplink data are pending for the corresponding PDUsession identity or the PDU session is in PDU SESSION INACTIVE state oris in PDU SESSION ACTIVE state with user-plane resources alreadyestablished.1 indicates that uplink data are pending for the corresponding PDUsession identity and the user-plane resources for the corresponding PDUsession are not established.All bits in octet 5 to 34 are spare and shall be coded as zero, if therespective octet is included in the information element.

FIG. 5 illustrates allowed PDU session status coding according to anembodiment of the disclosure.

The purpose of the Allowed PDU session status IE is to indicate to thenetwork user-plane resources of PDU sessions associated with non-3GPPaccess that are allowed to be re-established over 3GPP access or ifthere is no PDU session(s) for which the UE allows the user-planeresources to be re-established over 3GPP access.

Referring to FIG. 5, the Allowed PDU session status is a type 4information element with minimum length of 4 octets and maximum lengthof 34 octets.

PSI(x) shall be coded as follows.

PSI(0):

Bit 1 octet 3 is spare and shall be coded as zero.

PSI(1)-PSI(15):

0 indicates that the user-plane resources of corresponding PDU sessionis not allowed to be re-established over 3GPP access.1 indicates that the user-plane resources of corresponding PDU sessioncan be re-established over 3GPP access.If there is no PDU session for which the user-plane resources can bere-established over 3GPP access, all bits in PSI(1)-PSI(15) shall becoded as zero.All bits in octet 5 to 34 are spare and shall be coded as zero, if therespective octet is included in the information element.

FIG. 6 illustrates PDU session status coding according to an embodimentof the disclosure.

The purpose of the PDU session status IE is to indicate the state ofeach PDU session that can be identified by a PDU session identity.

Referring to FIG. 6, the PDU session status information element is atype 4 information element with minimum length of 4 octets and a maximumlength of 34 octets.

PSI(x) shall be coded as follows.

PSI(0): Bit 1 of octet 3 is spare and shall be coded as zero.

PSI(1)-PSI(15):

0 indicates that the SGSM state of the corresponding PDU session is PDUSESSION INACTIVE.1 indicates that the SGSM state of the corresponding PDU session is notPDU SESSION INACTIVE.All bits in octet 5 to 34 are spare and shall be coded as zero, if therespective octet is included in the information element.

Based on the analysis above, it is clear that the maximum number of PDUsessions that can be supported by any UE is 15.

In the related art, the maximum number of PDU session IDs limits thenumber of PDU sessions, and hence remote UEs, that can be served by arelay UE. This is especially the case when all or most of the remote UEsare using Unstructured PDU session types, as referenced previously. Thisallows only a single remote UE to be supported by the relay UE.

An extended number of PDU sessions is desirable for UE-to-Network Relay,in particular for Unstructured type PDU Session.

In the related art, if there are more than 16 remote UEs that need toobtain services via the same relay UE, then only 15 UEs will be able toconnect via the relay UE, if all remote UEs require to use a PDU sessionhaving Unstructured data type.

It is an aim of embodiments of the disclosure to address this and othershortcomings.

In order to address the problems in the related art, a relay UE shouldsupport more than 15 PDU sessions in order to serve more than 15 remoteUEs. However, supporting more than 15 PDU sessions requires thefollowing changes to related art systems:

-   -   The UE and the network (e.g., an access and mobility management        function, AMF or the RAN) exchange their capabilities with        respect to the number of PDU sessions that can be supported.    -   The relevant information elements, IE, are extended such that        new values for the PDU session ID beyond the related art value        of 15 can be defined and used.

Embodiments of the disclosure provide that the UE and the networkshould, in general, exchange new capabilities to indicate whether or notthey support more than 15 PDU sessions, hereafter referred to asincreased number of PDU sessions (when compared to the related art).

There are a number of ways to achieve this aim and the followingdescription sets these out.

In an embodiment of the disclosure, the UE uses a new bit in the 5Gmobility management (SGMM) capability IE to indicate if it supports anincreased number of PDU sessions. For example, a new “Support forincreased number of PDU sessions” bit is defined, where the value “1” isused to indicate “Increased number of PDU sessions supported” and thevalue “0” is used to indicate “Increased number of PDU sessions notsupported”.

Similarly, the AMF (e.g., in addition to/or another network entity,e.g., RAN) indicates if an increased number of PDU sessions is supportedin the network or PLMN. A new bit, e.g., in the 5GS network featuresupport IE can be used to indicate this. For example, a new “Support forincreased number of PDU sessions” bit is defined, where the value “1” isused to indicate “Increased number of PDU sessions supported” and thevalue “0” is used to indicate “Increased number of PDU sessions notsupported”. Other IEs and/or fields may be also used, e.g., when theexchange of capabilities happen using RRC signaling.

Note that the support of increased number of PDU session may be used toindicate that a fixed number of PDU sessions is supported, where thisnumber can be any integer N that is pre-determined. For example, withN=64, the use of the bits as set out above would implicitly mean thatthe UE or the network supports 64 PDU sessions. It should be noted thatthe value N=64 is an example only, and other pre-determined values canalso be defined for this purpose.

Although not explicitly stated, it is understood that the 5GMMcapability IE is sent by the UE in the Registration Request message, andthe 5GS network feature support IE is sent by the AMF in theRegistration Accept message.

Optionally, and perhaps in addition to the details of the embodimentabove, the UE and the network (e.g., AMF, RAN, or the like) canexplicitly indicate the maximum number of PDU sessions that can besupported. To do so, a new IE is defined for this purpose. For example,a new Number of supported PDU sessions IE is defined and is sent by theUE to indicate an integer number that represents the total number of PDUsessions that the UE can support. Note that this IE may also be used toindicate the additional number of PDU sessions that the UE can supporton top of 15 PDU sessions that is assumed to be supported by the UE. TheUE sends this IE in the Registration Request message where, optionally,the message is not being sent due to periodic update (i.e., this IEshould not be sent when the 5GS registration type IE indicates “periodicregistration updating”) and so the IE is sent for all other valuesindicated by the 5GS registration type IE except “periodic registrationupdating”.

The AMF receives the new IE indicating the total number of PDU sessionsthat is supported by the UE, or the additional number of PDU sessionsthat is supported by the UE (i.e., in addition to an assumed 15 PDUsessions). The AMF receives this IE in the Registration Request message.The AMF then determines the maximum number of PDU sessions that can beused by the UE as follows:

-   -   If the total number of PDU sessions that the network (e.g., AMF        and/or RAN, or the like) supports is less than the total number        that the UE indicates, then the AMF determines the maximum        number of PDU sessions for this UE to be the total number of PDU        sessions that the AMF (and/or RAN, or the like) supports.    -   If the total number of PDU sessions that the network (e.g., AMF        and/or RAN, or the like) supports is more than the total number        that the UE indicates, then the AMF determines the maximum        number of PDU sessions for this UE to be the total number of PDU        sessions that the UE supports.

Note: the above means that the total number of PDU sessions that can beused by the UE is equal to min{maximum number of PDU sessions supportedby the AMF (and/or RAN, or the like), maximum number of PDU sessionsthat is supported by the UE} or is equal min{maximum number of PDUsessions supported by the AMF, maximum number of PDU sessions supportedby the SMF, maximum number of PDU sessions supported by the RAN, maximumnumber of PDU sessions that is supported by the UE}. It should be notedthat the formula provided above is an example and the actual formula mayconsist of fewer elements and/or combinations.

When the AMF determines the maximum number of PDU sessions that can beused by the UE in question, the AMF sends a new IE in the RegistrationAccept message to indicate the maximum number of PDU sessions that canbe used by the UE. The indicated number is based on the determinednumber as explained above. The AMF may use new IE which can be called,e.g., Number of supported PDU sessions IE or Number of allowed PDUsessions IE. This IE indicates an integer number that represents thetotal number of PDU sessions that the UE can use or that is allowed foruse by the UE, as explained above. The AMF may also inform the RAN aboutthe support of more than 15 PDU session identity for the UE in questionand may also indicate the actual number that is supported. The AMF maydo so using any message that is used on the protocol between the AMF andthe RAN (e.g., on the N2 interface). Any existing or new IE/field may beused to do so.

When the UE receives an indication from the network that an increasednumber of PDU sessions is supported or allowed for the UE, the UEdetermines that an increased number of PDU sessions can be used in thisnetwork and optionally determines the number that is supported orallowed in the network using any of the following options, in anycombination:

-   -   The UE may determine the total number of PDU sessions that is        supported or allowed based on a pre-determined value. For        instance, the pre-determined value can be an integer N of        supported number of PDU sessions.    -   The UE may determine the total number of PDU sessions that is        supported or allowed based on a value that is received in a new        IE in the Registration Accept message. This value may represent        a total number of PDU sessions that is allowed or supported for        the UE, or an additional value on top of 15 PDU sessions that is        assumed to be supported by the network and hence the total        number is determined to be 15 plus the additional value that is        indicated to the UE by means of a new IE in the Registration        Accept message.    -   The UE may determine the total number of PDU sessions that is        supported or allowed based on a value that is received in from        the RRC layer, where the RRC layer provides this indication to        the NAS, e.g., based on an RRC message that is received from the        RAN, where the message may be a broadcast message or a dedicated        message (or RRC signaling message).

Note that the indication referred to above can be a new bit (e.g., inthe 5GS network feature support IE) and/or a new IE in the RegistrationAccept message and/or a new bit or information in an RRC message or aSGSM message.

The new IE that is set out above, either to be sent by the UE or by thenetwork, or both, can be of the form TV (Type and Value) or TLV (Type,Length, and Value).

When the UE determines that an increased number of PDU sessions can besupported, or is allowed for the UE in this network or PLMN, the UE mayuse a PDU session ID whose value can be more than 15 up to the maximumnumber of PDU sessions that the UE has determined to be supported, or isallowed in the network, as explained above.

To support an increased number of PDU sessions as set out above, certainrelated art IEs need to be updated to enable this increase. For example,the PDU session identity IE needs to be updated such that new values aredefined and used by either the UE or the network. The new values can bedefined accordingly to, e.g., start from the value 16 up to the maximumnumber of PDU sessions that has been determined to be allowed orsupported for the UE in the network.

Similarly, the Uplink data status IE, Allowed PDU session status IE, andthe PDU session status IE need to be updated accordingly. For example,more octets and bit positions may be used and defined to represent thenew PDU session ID values. As such, these IEs are adapted to have theirreserved fields updated to now represent the new PDU session ID wheremore octets can be defined depending on the maximum number of PDUsessions that are allowed or supported for the UE. Note that otheridentities, e.g., a bearer ID that may be used in the RRC layer, canalso be updated accordingly.

When an increased number of PDU sessions is supported by both the UE andthe network, then both the UE and the network use the updated IEs tomatch the maximum number of PDU sessions that are supported or allowedfor the UE.

For example, if the UE and/or the network determine that the maximumnumber of PDU sessions that can be used for the UE is 31, then the PDUsession identity IE (or any other IE that is of the same type, e.g., PDUsession identity 2, or the like) can have values that are extended,where the extension starts with the value 16 up until 31. Similarly, allthe other IEs, e.g., PDU session status IE, or the like, that have abitmap representing PDU session IDs can in turn be extended to enable abitmap that represents the value 16 to 31.

In one example, the PDU session status IE can now use two additionaloctets (e.g., octets 5 and 6) with new bit positions, where each bitrepresents the extended values, i.e., 16 to 31 in this example. Notethat this is just an example and should not be considered to belimiting. Hence the same solution would apply if the extended value isdifferent from 31 (i.e., either less than or greater than 31) and theextended values and bitmaps of the necessary IEs can also be modifiedaccordingly.

Note that extension of the PDU session ID implies that the AS alsosupports more data radio bearers, and there should be a one to onemapping between the PDU session ID and a DRB ID. As such, the DRBidentities should also be updated accordingly.

Note that the AS layer in the UE may also inform the RAN about thesupport of increased number of PDU session. This can be done using anyform of an indication at the AS layer, e.g., a new bit or new IE in anyRRC message or, optionally, any IE that contains capability informationof the UE. The indication may also provide the exact number of PDUsessions that can be supported for the UE.

Optionally, the AMF may inform the (R)AN about the use of increasednumber of PDU session for the UE. This indication may be sent in anymessage over the N2 interface (i.e., interface between the (R)AN and theAMF. The indication may be in the form of a bit or an IE and may alsoprovide the exact number of PDU sessions that can be supported for theUE.

The following describes other actions taken by the network when anincreased number of PDU session ID is used as set out herein.

When a UE (e.g., a relay UE) requests to establish a new PDU session forwhich the PDU session ID represents a value that is above 15, i.e., thevalue used by the UE is one of the extended or new values for the PDUsession ID, the selection of an SMF by the AMF should consider thesupport of extended or increased PDU session ID by the SMF. Thus, theAMF should select an SMF that is capable of supporting and handling aPDU session ID for which the value is increased beyond 15. The AMF'sselection policy, i.e., the policy used to select an SMF, should nowconsider the support of increased number of PDU session ID and thereforethe AMF should select an SMF that supports increased number of PDUsessions.

Upon reception of an UL NAS TRANSPORT message with a SGSM message andfor which the request type indicates “initial request”, the AMF shouldconsider the PDU session ID value when selecting an SMF as describedabove. If an SMF that supports an increased number of PDU session IDcannot be selected, the AMF should send a DL NAS TRANSPORT message andinclude the SGSM message that could not be forwarded to any SMF. The AMFshould also include a new or existing 5GMM cause code to indicate areason why the 5GSM message cannot be forwarded. For example, a new 5GMMcode value set to “SMF supporting increased PDU session ID not found”may be used. However, this is just an example and other values, evenexisting related art values, can be used instead.

It may also be possible (and hence is described as an embodiment) thatthe use of a set of slices requires the support of a PDU sessionidentity that is greater than 15. Alternatively, the slices that may beallowed for a UE may be such that they support a PDU session identitythat is more than 15. This set of slices may be determined from thesubscription and/or local AMF policy. Any such slice that is provided tothe UE, e.g., by the AMF, may also include an indication that the sliceis associated with a PDU session identity that is greater than 15, orthat can be used with an identity that is greater than 15.

The following describes other actions taken by a UE when an increasednumber of PDU session ID is used as set out herein:

A UE (e.g., a relay UE or a discoveree UE should indicate in the PC5discovery message(s) whether it supports:

-   -   extended number of PDU sessions (i.e., support for increased        number of PDU sessions), or    -   the UE may indicate the maximum number of PDU sessions where        this number may represent the number of PDU sessions that can be        supported in total, or that are still available or vacant and        may optionally refer to the number of new remote UEs that can be        served/accommodated/accepted optionally for a particular PDU        session type, e.g., Unstructured PDU session type or    -   the UE may implicitly indicate whether there are still available        or vacant PDU sessions via Service and application information        that is enabled or authorized to be relayed.

This can be indicated in the PC5 discovery message that is either sentfor Model A or Model B PC5 discovery procedures. The relay UE mayoptionally indicate how many more PDU sessions it can support for aparticular PDU session type, e.g., Unstructured session type. The UE mayalso indicate if it can accept more remote UEs, optionally, where thisindication may be per PDU session type. For example, if the UE inquestion is a relay UE and the number of supported PDU sessions(regardless of this number being extended or not) has not been exhaustedyet, the UE may indicate that it can accommodate new remote UEsoptionally for a particular PDU session type, e.g., unstructured PDUsession type. When the UE reaches its maximum number of PDU sessionsi.e., no new PDU session can be further established (e.g., due to thePDU session ID reaching the maximum value that can be supported), the UEmay stop indicating that it can accommodate new UEs, e.g., remote UEs,optionally for a particular PDU session type, e.g., Unstructured PDUsession type. If a PDU session (ID) becomes vacant in the relay UE, thenthe relay UE may again start sending an indication that it can supportnew remote UE(s) optionally for a particular PDU session type, e.g.,unstructured PDU session type. Note that the above indications can beincluded in PC5 discovery messages for Model A or Model B PC5 discoveryprocedures. Note that the above behavior may be performed for Model APC5 discovery or for Model B PC5 discovery where, for the latter, the UEmay take the actions above optionally after receiving a request (e.g.,solicitation via a, e.g., PC5 discovery message) from another UE todiscover a particular relay UE with certain capabilities as explainedbelow.

Note that the relay UE may receive more than one PC5 discovery messagefor Model B i.e., a solicitation discovery message, where the sending UErequests the discovery of a UE, e.g., a relay UE, with certaincapabilities, such as the ability to provide service or accommodate anew UE (e.g., a remote UE) optionally for a particular PDU session type,e.g., unstructured PDU session type. The UE may prioritize its responseto the sending UEs based on any of the following:

-   -   Based on the time that the discovery message was received.        Hence, the relay UE will first respond to the UE from which the        discovery message (i.e., solicitation message) was first        received.    -   Based on the slice (S-NSSAI) that is being discovered, where the        relay UE may be, e.g., configured with a list of S-NSSAIs each        of which has an associated priority. Hence the relay UE may        first respond to the UE that requests a particular S-NSSAI if        that S-NSSAI is considered to be of higher priority than another        S-NSSAI that may have been requested by another UE. This may be        done regardless of the time that the discovery message was        received.    -   Based on the Data Network Name (DNN) that is being discovered,        where the relay UE may be, e.g., configured with a list of DNNs        each of which has an associated priority. Hence the relay UE may        first respond to the UE that requests a particular DNN if that        DNN is considered to be of higher priority than another DNN that        may have been requested by another UE. This may be done        regardless of the time that the discovery message was received.    -   Based on the ProSe discovery code (e.g., a relay service code),        or group ID, that is being discovered, where the relay UE may        be, e.g., configured with a list of ProSe discovery code (e.g.,        a relay service code), or group ID, each of which has an        associated priority. Hence the relay UE may first respond to the        UE that requests a particular ProSe discovery code (e.g., a        relay service code), or group ID, if that ProSe discovery code        (e.g., a relay service code), or a group ID, is considered to be        of higher priority than another DNN that may have been requested        by another UE. This may be done regardless of the time that the        discovery message was received.    -   Any combination of the above

Note that for any of the above, if the priority of the parameter inquestion is the same, i.e., as requested from more than one UE, therelay UE may choose a UE to respond to first based on implementation,e.g., using a random selection.

A UE (e.g., a remote UE or discoverer UE) may participate in a Model Bdiscovery over the PC5 interface where the UE can request the discoveryof UEs (e.g., relay UEs) that support:

-   -   extended or increased number of PDU sessions or PDU session IDs,        or    -   where the solicitation message (i.e., a discovery message)        requests the discoveree UE (e.g., a relay UE) to indicate the        maximum number of PDU sessions that are supported. Note that        this number may represent the number of PDU sessions that can be        supported in total, or that are still available or vacant and        may optionally refer to the number of new remote UEs that can be        served/accommodated/accepted optionally for a particular PDU        session type, e.g., unstructured PDU session type.

The UE may send a PC5 discovery message for Model B discovery in whichit indicates that the UE wants to discover (or solicits the discoveryof) another UE (e.g., a UE-to-Network relay) which supports increasednumber of PDU sessions, optionally for Unstructured PDU session type.Alternatively, the UE may send a PC5 discovery message for Model Bdiscovery in which it indicates that the UE wants to discover (orsolicits the discovery of) another UE (e.g., a UE-to-Network relay)which can accommodate a new UE (e.g., a remote UE) optionally for aparticular PDU session type, e.g., unstructured PDU session type.

A UE may receive a PC5 discovery message from another UE (e.g., a relayUE) indicating that the sending UE supports:

-   -   extended or increased number of PDU session (ID), optionally for        Unstructured PDU session type, or    -   can accept/serve/accommodate more remote UEs, optionally where        this indication may be per PDU session type, e.g., unstructured        PDU session type, or    -   the maximum number of PDU sessions that are supported. Note that        this number may represent the number of PDU sessions that can be        supported in total, or that are still available or vacant and        may optionally refer to the number of new remote UEs that can be        served/accommodated/accepted optionally for a particular PDU        session type, e.g., unstructured PDU session type.

The UE may also receive another similar message from another senderwhere the discovery message contains similar information as listedabove, e.g., the discovery message may indicate that the other sendingUE does not support extended or increased PDU session (ID). Thediscoverer UE (e.g., a remote UE) may select the target UE (e.g., aUE-to-Network relay UE) which:

-   -   supports an extended or increased PDU session (ID) over the        other UE which does not, or    -   can accommodate/serve/accept more remote UEs, optionally where        this indication may be per PDU session type, e.g., unstructured        PDU session type, or    -   has a larger maximum number of PDU sessions that are/can be        supported.

This may be done optionally if the discoverer UE requires a PDU sessionfor Unstructured data type.

Note that all of the above can also apply to a remote UE, whereoptionally the remote UE communicates with the network using a (layer-2or layer-3) UE-to-network relay UE.

All of the above herein may apply in any combination or order.

Moreover, the detailed description herein can apply to any UE in Si mode(i.e., in EPS/EPC) where the relevant NAS messages (which may bedifferent but considered to be equivalent) can be used accordingly withthe appropriate IEs or fields, or the like. As such, the network nodesused herein may also be network nodes in EPS/EPC and the proposals wouldapply in a similar manner for a UE and/or network in Si mode.

FIG. 7 illustrates a structure of a user equipment (UE) according to anembodiment of the disclosure.

Referring to FIG. 7, a UE 700 may include a controller 710, atransceiver 720 and a memory 730. However, all of the illustratedcomponents are not essential. The UE 700 may be implemented by more orless components than those illustrated in FIG. 7. In addition, thecontroller 710 and the transceiver 720 and the memory 730 may beimplemented as a single chip according to another embodiment.

The UE 700 may correspond to a UE described above.

The aforementioned components will now be described.

The controller 710 may include one or more processors or otherprocessing devices that control the proposed function, process, and/ormethod. Operation of the UE 700 may be implemented by the controller710.

The transceiver 720 may include a RF transmitter for up-converting andamplifying a transmitted signal, and a RF receiver for down-converting afrequency of a received signal. However, according to another embodimentof the disclosure, the transceiver 720 may be implemented by more orless components than those illustrated in components.

The transceiver 720 may be connected to the controller 710 and transmitand/or receive a signal. The signal may include control information anddata. In addition, the transceiver 720 may receive the signal through awireless channel and output the signal to the controller 710. Thetransceiver 720 may transmit a signal output from the controller 710through the wireless channel.

The memory 730 may store the control information or the data included ina signal obtained by the UE 700. The memory 730 may be connected to thecontroller 710 and store at least one instruction or a protocol or aparameter for the proposed function, process, and/or method. The memory730 may include read-only memory (ROM) and/or random access memory (RAM)and/or hard disk and/or CD-ROM and/or DVD and/or other storage devices.

FIG. 8 illustrates a structure of a base station according to anembodiment of the disclosure.

In the disclosure, a base station may be the entity that allocatesresources to a UE, and may be one of an eNode B, a gNode B, Node B, abase station (BS), a radio access network (RAN), an access network (AN).

Referring to FIG. 8, a base station 800 may include a controller 810, atransceiver 820 and a memory 830. However, all of the illustratedcomponents are not essential. The base station 800 may be implemented bymore or less components than those illustrated in FIG. 8. In addition,the controller 810 and the transceiver 820 and the memory 830 may beimplemented as a single chip according to another embodiment.

The base station 800 may correspond to a base station described above.

The aforementioned components will now be described.

The controller 810 may include one or more processors or otherprocessing devices that control the proposed function, process, and/ormethod. Operation of the base station 800 may be implemented by thecontroller 810.

The transceiver 820 may include a RF transmitter for up-converting andamplifying a transmitted signal, and a RF receiver for down-converting afrequency of a received signal. However, according to another embodimentof the disclosure, the transceiver 820 may be implemented by more orless components than those illustrated in components.

The transceiver 820 may be connected to the controller 810 and transmitand/or receive a signal. The signal may include control information anddata. In addition, the transceiver 820 may receive the signal through awireless channel and output the signal to the controller 810. Thetransceiver 820 may transmit a signal output from the controller 810through the wireless channel.

The memory 830 may store the control information or the data included ina signal obtained by the base station 800. The memory 830 may beconnected to the controller 810 and store at least one instruction or aprotocol or a parameter for the proposed function, process, and/ormethod. The memory 830 may include read-only memory (ROM) and/or randomaccess memory (RAM) and/or hard disk and/or CD-ROM and/or DVD and/orother storage devices.

FIG. 9 illustrates a structure of a network entity according to anembodiment of the disclosure.

In the disclosure, a network entity may be the entity performing networkfunctions (e.g, access and mobility management function (AMF), sessionmanagement function (SMF), and the like). In the disclosure, forconvenience, an entity performing an AMF may be expressed as AMF or AMFentity. Further, in the disclosure, for convenience, an entityperforming a SMF may be expressed as SMF or SMF entity. In addition, forconvenience, an entity performing a function may be abbreviated anddescribed as the name of the function.

Referring to FIG. 9, a network entity 900 may include a controller 910,a transceiver 920 and a memory 930. However, all of the illustratedcomponents are not essential. The network entity 900 may be implementedby more or less components than those illustrated in FIG. 9. Inaddition, the controller 910 and the transceiver 920 and the memory 930may be implemented as a single chip according to another embodiment.

The network entity 900 may correspond to an AMF or a SMF describedabove.

The aforementioned components will now be described.

The controller 910 may include one or more processors or otherprocessing devices that control the proposed function, process, and/ormethod. Operation of the network entity 900 may be implemented by thecontroller 910.

The transceiver 920 may be connected to the controller 910 and transmitand/or receive a signal to/from other entities. The signal may includecontrol information and data.

The memory 930 may store the control information or the data included ina signal obtained by the network entity 900. The memory 930 may beconnected to the controller 910 and store at least one instruction or aprotocol or a parameter for the proposed function, process, and/ormethod. The memory 930 may include read-only memory (ROM) and/or randomaccess memory (RAM) and/or hard disk and/or CD-ROM and/or DVD and/orother storage devices.

At least some of the example embodiments described herein may beconstructed, partially or wholly, using dedicated special-purposehardware. Terms, such as ‘component’, ‘module’ or ‘unit’ used herein mayinclude, but are not limited to, a hardware device, such as circuitry inthe form of discrete or integrated components, a field programmable gatearray (FPGA) or application specific integrated circuit (ASIC), whichperforms certain tasks or provides the associated functionality. In someembodiments of the disclosure, the described elements may be configuredto reside on a tangible, persistent, addressable storage medium and maybe configured to execute on one or more processors. These functionalelements may in some embodiments include, by way of example, components,such as software components, object-oriented software components, classcomponents and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables. Although the example embodiments have been described withreference to the components, modules and units discussed herein, suchfunctional elements may be combined into fewer elements or separatedinto additional elements. Various combinations of optional features havebeen described herein, and it will be appreciated that describedfeatures may be combined in any suitable combination. In particular, thefeatures of any one example embodiment may be combined with features ofany other embodiment of the disclosure, as appropriate, except wheresuch combinations are mutually exclusive. Throughout this specification,the term “comprising” or “comprises” means including the component(s)specified but not to the exclusion of the presence of others.

Attention is directed to all papers and documents which are filedconcurrently with or previous to this specification in connection withthis application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of theoperations of any method or process so disclosed, may be combined in anycombination, except combinations where at least some of such featuresand/or operations are mutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings) may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The disclosure is not restricted to the details of the foregoingembodiment(s). The disclosure extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the operations of any method or process sodisclosed.

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a user equipment (UE) in acommunication system, the method comprising: transmitting, toward anaccess and mobility management (AMF) entity, a registration requestmessage including first information indicating whether the UE supportsan increased number of protocol data unit (PDU) sessions; receiving,from the AMF entity, a registration accept message including secondinformation indicating whether a network supports the increased numberof PDU sessions; and identifying whether the increased number of PDUsessions is allowed to be used based on at least one of the firstinformation or the second information.
 2. The method of claim 1, whereinthe first information is in capability information for the UE includedin the registration request message, and wherein the second informationis in support feature information for the network included in theregistration accept message.
 3. The method of claim 1, wherein a maximumnumber of PDU sessions is based on whether the increased number of PDUsessions is allowed.
 4. The method of claim 3, wherein at least one ofPDU session identity information element (IE), uplink data status IE, orallowed PDU session status IE is based on the maximum number of PDUsessions, and wherein, in case that the increased number of PDU sessionsis allowed to be used, the maximum number of PDU sessions is greaterthan
 15. 5. The method of claim 4, further comprising: transmitting,toward the AMF entity, a request message for establishing a PDU sessionfor which a PDU session identity (ID) associated with an extended valueaccording to the increased number of PDU sessions, wherein a sessionmanagement function (SMF) entity is selected by the AMF entity based onwhether the SMF entity supports the increased number of PDU sessions. 6.A method performed by an access and mobility management function (AMF)entity in a communication system, the method comprising: receiving, froma user equipment (UE), a registration request message including firstinformation indicating whether the UE supports an increased number ofprotocol data unit (PDU) sessions; and transmitting, to the UE, aregistration accept message including second information indicatingwhether a network supports the increased number of PDU sessions, whereinwhether the increased number of PDU sessions is allowed to be used isbased on at least one of the first information or the secondinformation.
 7. The method of claim 6, wherein the first information isin capability information for the UE included in the registrationrequest message, and wherein the second information is in supportfeature information for the network included in the registration acceptmessage.
 8. The method of claim 6, wherein a maximum number of PDUsessions is based on whether the increased number of PDU sessions isallowed.
 9. The method of claim 8, wherein at least one of PDU sessionidentity information element (IE), uplink data status IE, or allowed PDUsession status IE is based on the maximum number of PDU sessions, andwherein, in case that the increased number of PDU sessions is allowed tobe used, the maximum number of PDU sessions is greater than
 15. 10. Themethod of claim 9, further comprising: receiving, from the UE, a requestmessage for establishing a PDU session for which a PDU session identity(ID) associated with an extended value according to the increased numberof PDU sessions; and selecting a session management function (SMF)entity supporting the increased number of PDU sessions.
 11. A userequipment (UE) in a communication system, the UE comprising: atransceiver; and at least one processor configured to: transmit, towardan access and mobility management (AMF) entity via the transceiver, aregistration request message including first information indicatingwhether the UE supports an increased number of protocol data unit (PDU)sessions, receive, from the AMF entity via the transceiver, aregistration accept message including second information indicatingwhether a network supports the increased number of PDU sessions, andidentify whether the increased number of PDU sessions is allowed to beused based on at least one of the first information or the secondinformation.
 12. The UE of claim 11, wherein the first information is incapability information for the UE included in the registration requestmessage, and wherein the second information is in support featureinformation for the network included in the registration accept message.13. The UE of claim 11, wherein a maximum number of PDU sessions isbased on whether the increased number of PDU sessions is allowed. 14.The UE of claim 13, wherein at least one of PDU session identityinformation element (IE), uplink data status IE, or allowed PDU sessionstatus IE is based on the maximum number of PDU sessions, and wherein,in case that the increased number of PDU sessions is allowed to be used,the maximum number of PDU sessions is greater than
 15. 15. The UE ofclaim 14, wherein the at least one processor is further configured to:transmit, toward the AMF entity via the transceiver, a request messagefor establishing a PDU session for which a PDU session identity (ID)associated with an extended value according to the increased number ofPDU sessions, wherein a session management function (SMF) entity isselected by the AMF entity based on whether the SMF entity supports theincreased number of PDU sessions.
 16. An access and mobility managementfunction (AMF) entity in a communication system, the AMF entitycomprising: a transceiver; and at least one processor configured to:receive, from a user equipment (UE) via the transceiver, a registrationrequest message including first information indicating whether the UEsupports an increased number of protocol data unit (PDU) sessions, andtransmit, to the UE via the transceiver, a registration accept messageincluding second information indicating whether a network supports theincreased number of PDU sessions, wherein whether the increased numberof PDU sessions is allowed to be used is based on at least one of thefirst information or the second information.
 17. The AMF entity of claim16, wherein the first information is in capability information for theUE included in the registration request message, and wherein the secondinformation is in support feature information for the network includedin the registration accept message.
 18. The AMF entity of claim 16,wherein a maximum number of PDU sessions is based on whether theincreased number of PDU sessions is allowed.
 19. The AMF entity of claim18, wherein at least one of PDU session identity information element(IE), uplink data status IE, or allowed PDU session status IE is basedon the maximum number of PDU sessions, and wherein, in case that theincreased number of PDU sessions is allowed to be used, the maximumnumber of PDU sessions is greater than
 15. 20. The AMF entity of claim19, wherein the at least one processor is further configured to:receive, from the UE via the transceiver, a request message forestablishing a PDU session for which a PDU session identity (ID)associated with an extended value according to the increased number ofPDU sessions, and select a session management function (SMF) entitysupporting the increased number of PDU sessions.